CVE-2024-39912

MEDIUM5.3EPSS 0.23%

The FIDO2/Webauthn Support for PHP library allows enumeration of valid usernames

發布日:2024/7/15修改日:2024/7/15
也稱為:GHSA-875x-g8p7-5w27

描述

### Summary The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. ### Details When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. #### Proposal how to resolve it: ``` return $this->publicKeyCredentialRequestOptionsFactory->create( $this->profile, count($allowedCredentials) <= 0 ? self::getRandomCredentials(): $allowedCredentials, $optionsRequest->userVerification, $extensions ); private static function getRandomCredentials(): array { $credentialSources = []; for ($i = 0; $i <= rand(0,1); $i++) { $credentialSources[] = new PublicKeyCredentialSource( random_bytes(32), "public-key", [], "basic", new EmptyTrustPath(), Uuid::v7(), random_bytes(77), Uuid::v7()->__toString(), rand(0, 6000), null ); } return array_map( static fn (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor => $credential->getPublicKeyCredentialDescriptor(), $credentialSources ); } ``` ### PoC curl https://example.com/assertion/options \ -H 'content-type: application/json' \ --data-raw '{"username":"NotMeRandomUsername123"}' ### Impact By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks.

受影響套件(2)

CVSS 分數

來源版本嚴重程度向量
osvCVSS 4.0—CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
osvCVSS 3.1MEDIUM5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

參考連結(6)